ML12243A435
| ML12243A435 | |
| Person / Time | |
|---|---|
| Site: | Palo Verde  |
| Issue date: | 08/30/2012 |
| From: | Hansen D Arizona Public Service Co |
| To: | Plant Licensing Branch IV |
| Gibson L | |
| References | |
| Download: ML12243A435 (23) | |
Text
Request for Relief 48 Request for Relief 48 q
Phased Phased Array Ultrasonic Examination Array Ultrasonic Examination in lieu of in lieu of Radiography Radiography Ari ona P blic Ser ice Compan Ari ona P blic Ser ice Compan Arizona Public Service Company Arizona Public Service Company Douglas Hansen Sr Consulting Engineer & Level III
Agenda
- Applicable codes R li f R t 48 S
- Relief Request 48 Scope
- Reason for Relief Request 48
- Code Case N-659-2 Paragraph summary comparison (Attachment 2 of Relief Request)
P
/T h i V lid ti
- Process/Technique Validation Sample comparison graphics
- Conclusion
Applicable Codes
- Construction Code ASME III
- 1974 Edition, Winter 1975 Addenda
- Repairs/Replacements
Scope ASME Class 2 piping circumferential butt welds Carbon steel base and weld metal Thickness > 0.337 Diameters >
6 NPS Geometry shall allow 100% coverage Weld and 1/2 base metal on each side Weld and 1/2 base metal on each side PVNGS Units 1, 2 and 3 for the 3rd interval Unit 1 thru 7-17-2018 Unit 2 thru 3-17-2017 Unit 3 thru 1-10-2018
=
Reason for Request===
Personnel - using Phased Array Ultrasonic Examination Technique (PAUT) reduces:
Exposure risk Dose Crew size Outage - using PAUT:
Reduces time for results Reduces time for results Reduces impact to the schedule Allows adjacent work to proceed Reduces risk (errors) associated with
(
)
starting/stopping/rescheduling critical activities Quality - using PAUT:
Increases critical flaw detection Increases critical flaw detection Provides flaw depths for repairs Recorded data for reviews and retention
Code Case N-659-2 Inquiry: Under what conditions and limitations may an ultrasonic examination be used in lieu of radiography where radiography is required by NB-5200, be used in lieu of radiography where radiography is required by NB 5200, NC-5200, ND-5200, WB-5200 or WC-5200, and substitution of ultrasonic examination would not otherwise be permitted?
Reply: It is the opinion of the Committee that all welds may be examined using the ultrasonic (UT) method in lieu of the radiographic (RT) method, provided that all of the following requirements are met:
provided that all of the following requirements are met:
N-659-2 (a) Examination Area Additional restrictions:
100% coverage (in all 4 directions)
Weld ground flush Surface examination (PT or MT)
S f
E A B Surface examination (PT or MT)
Surface Exam A-B 1/2 1/2 A
B C
D PAUT Exam Volume A-B-C-D
N-659-2 (b) Examination Procedure Additional restrictions:
ASME Section V Article 4; 2001 Edition, 2003 Addenda PAUT with minimum of 40-70 degrees Volume scanned with 0 degree Volume scanned with 0 degree N 659 2 ( ) P d
D t
ti Additional restrictions:
Demonstration for each nominal diameter and thickness N-659-2 (c) Procedure Demonstration Demonstration for each nominal diameter and thickness Essential and non-essential requirements documented
N-659-2 (d) Qualification Blocks Additional restrictions:
For each nominal diameter and thickness 6 9 2 ( )
i l Additional restrictions:
None; cast and austenitic products are not included N-659-2 (e) Materials None; cast and austenitic products are not included N-659-2 (f) Examination Plan Additional restrictions:
None; an exam plan and sketch will be provided N-659-2 (f) Examination Plan
N-659-2 (g) Acceptance Criteria Additional restrictions:
ASME Section III; 2001 Edition, 2003 Addenda
N-659-2 (h) Pre-Service Examinations Additional restrictions:
Pre-Service Examinations (PSE) will be performed, when required, in addition to the proposed PAUT examinations Additional restrictions:
N-659-2 (i & j) Acquisition Additional restrictions:
None, examinations will be auto (encoded) and recorded Additional restrictions:
None for acquisition personnel; they will be qualified and N-659-2 (k) Acquisition Personnel None, for acquisition personnel; they will be qualified and trained using the same demonstrated equipment
N-659-2 (k) Analysis Personnel Additional restrictions:
They will demonstrate their capability to detect and characterize flaws; will utilized data acquired with the demonstrated procedure; and:
Detection ASME XI Table VIII-S2-1 Flawed grading units will be 1/4 longer than actual flaw longer than actual flaw Unflawed grading units will be a min of 1 At least 2 of the flaws will meet N-659-2 (d) sizes Sizing Flaws will be sized as being >
actual length Fl ill b l
Flaws will be properly categorized as surface or subsurface
Additi l
t i ti N-659-2 (l) ANII Additional restrictions:
None; review and acceptance of the ANII N 659 2 (m) Other Requirements Additional restrictions:
None; other related requirements will be met N-659-2 (m) Other Requirements N-659-2 (n) Repairs Additional restrictions:
None; flaws will be repaired and the weld re-examined Additional restrictions:
None; the Case number will be recorded N-659-2 (o) Code Case None; the Case number will be recorded
Process/Technique Validation PVNGS developed a set of actual weld flawed specimens Flaws totaled over 60 for Carbon Steel Porosity Incomplete fusion Incomplete penetration Incomplete penetration Slag Cracking S
i h
b di h d f i
Specimens have been radiographed for comparison Specimens are being digital radiographed for additional comparison
Process/Technique Validation
Process/Technique Validation RESULTS RESULTS PAUT detected all the RT indicated flaws PAUT detected several additional areas of incomplete fusion PAUT detected all of the cracks in the exam volume PAUT detected all of the cracks in the exam volume
14-100-CS SLAG RT ~1 length PAUT ~1 length
8-120-CS Incomplete Fusion RT ~1 intermittent PAUT
~1 length PAUT ~1 length
12-100-CS Incomplete Penetration RT ~ 3/4 length PAUT
~ 3/4 length PAUT 3/4 length
(~1.2 in other direction)
8-120-CS Porosity RT ~1 length PAUT ~1 length
10-60-CS ID Crack (PT)
RR 48 Summary Additional restrictions (requirements) to N-659-2:
Automated (encoded) Phased Array Ultrasonic Examination All welds will receive a surface (PT or MT) examination All welds will receive a surface (PT or MT) examination Weld caps will be ground flush Volume will be scanned in all 4 directions 100% coverage Volume will be scanned with a 0 degree Demonstration for each nominal diameter and thickness Data will be recorded for analysis and retention PSE will be in addition and per ASME Section XI PSE will be in addition and per ASME Section XI
Conclusion Conclusion RR 48 utilizes as a basis Code Case N-659-2 RR 48 requires additional restrictions RR 48 provides an acceptable level of quality and safety